BACKGROUND: Lacrosse is a fast growing youth sport in the United States. Although there have been published studies examining injuries associated with lacrosse, significantly less research has been conducted in high school lacrosse players than in older lacrosse players. The objective of this study was to compare high school lacrosse injury rates and patterns by type of athletic activity (ie, competition vs practice) and sex. HYPOTHESIS: Lacrosse injury rates and patterns differ by type of athletic activity and sex...